The whole mobileMe thing is just a wrapper over a load of different services you can pick up for free elsewhere. I sync contacts by using Plaxo (free) to keep contacts up to date across various desktop clients and Gmail contacts then get my iPhone to sync with my Gmail contacts. Gmail's calendar (synced with Thunderbird/Lightning) and accessed from the iPhone takes care of appointments.
As for mail, the whole point of IMAP is that you don't need to layer another service on top of it to have access to the same inbox from multiple accounts. And who needs yet another email address? And as for 20Gig of online storage, why not just use Amazon's S3 service via Jungledisk's web interface?